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' Patented July 21, 1 943 UNIIIZEDVSTAIESQ imam f OFFICE 1 Y i must i.

, B. AND mm comma Stanton A. warms, N. 1., m to Merck I: 00.. Inc.,'llahway, N. J., a

tion of New Jersey No Drawing. Original application December 21,- 1938, Serial No. mm. Divided andthia application July s,- io i, Serial No. 400,081

3 Claims. (01. see-29s) This invention relates to a process of preparing vitamin B0, and related compounds, and to new intermediate products made and employed in such process, and is a division of my co-pending ture is poured into 400 cc. of a mixture oi water and ice, whereupon crystals of the lactone oi 3-carboxy-4-hydroxymethyl-8-methylpyridone-2 appear. The mass is filtered and washed with water, the dried product weighing 11.1 ms. or,

application Serial No. 247,948, filed December 5 about.8'l% yield. Upon recrystallization from 27, 1938, now Patent No. 2,248,078. u water the crystals have a melting point oi I have discovered that these compounds may 320 C. (uncorrected). 1 T be synthesized by reacting ethoxyacetylacetone Alternatively, the lactoneoi 3-carboxy-4-hyand cyanoacetamide to form 3 -cya no-4-ethoxy- .droxymetlw1-6-methylpyridone-2 may be obmethyl-6-methylpyridone-2, hydrolyzing the latl0 tained by refluxing 93 gms. oi 3-cyano -4-ethoxyter compound to form the lactone of S-carboxy- -methyl-6-methylpyrid0ne-2 for three hours with a-hy droxyn' ethyl-6-methylpyridone-2,v treating 1120 cc. of 50% sulfuric acid, the temperature: the latter compoundwith nitric acid to form the of the liquid being 120 C. The reaction mixture lactone of 3-carboxy-4-hydroxymethyl-5-nitrois poured into 3.5-4.0 liters of water and placed- 6-methylpyridone-2, chlorinating the latter coinin an ice room overnight. The next day. the pound to form the lactone of 2-chloro-3-c'arboxycrystals are filtered 011., washed well with water.- 4-hydroxymethyl-5-nitro-6-methylpyridine; realcohol, and ether; and dried at atemperature ducing the latter compound to form the lactone oi 55-60 C. The yield is 70.5 gms. or 88.2% oi of 3-carboxy-4-hydroxymethyl-5-amino fi-meththeory. 4 ylpyridine, or alternatively, by reducing the I Twenty-eight g ms. of the lactone of S-carboxylactone of 2-chlor0-3-carb0xy-4-hydroxymethyl- 4-hydroxymethyl-fi-methylpyridone-2 are -dis- E- nitro-G-methyIpyridine to the lactone of .2- solved in 62 cc. of concentrated sulfuric acid, the chloro 3 -carboxy-4-hydroxymethyl-5-amino-6 solution is cooled, and added to an ice cold mixmethylpyridine, and reducing the latter comture of 124 cc. of concentrated sulfuric acid and pound to the lactone of 3 -carboxy-4-hydroxy- 52 cc. fuming nitric acid (sp. g. 1.5). The mixmethyl-5-amino 6 -methylpyridine, diazotizing ture warms spontaneously, reaching a temperathe latter compound to form the lactone of 3- ture of 35-45 C. Aiter this temperature starts carboxy- 4-hydroxymethyl-5-hydroxy-6-methylto fall, the mixture is cooled to 15 C. and pouredpyridine, and reducing the latter compound to onto crushed ice, the final volume being about form vitamin Ba. one liter. A yellow solid forms immediately, The following example illustrates one method which is filtered oi! and dried at 65 C. The of carrying out the present invention, but it is to yield of the lactone of 3'-carboxy--hydroxy'- be understood that the example is given by way methyl-5-nitro-6-methylpyridone-2 is 29.6 ms. of illustration and not of limitation. or 83.5%. On recrystallization from water, it E1 8 melts at 279 280. (1., with decomposition.

Fifteen and three tenths gms. of the lactone -five and three tenths sins. of cyanoof 3-carboxy-4-hydroxymethyl-5-nitro-6-methacetamide are dissolved in 500 cc. of hot 95% ylpyridone-2, cc. of phosphorus oxvchloride, alcohol and 93.1 gms. of ethoxyacetylacetone are a d an excess of phosphorus pentachloride added. wen y-five c. of p pe di a e then 40 are. mixed; and refluxed until solution added wi h sh kin wh p the mixture 1 occurs, which requires about of an hour. The comes warm. The solution is cooled and allowed phosphorus oxychloride is distilled oil under to stand Overni ht. a a and flltcrcdvacuo, whereupon a solid separates. The solid is The y tals are washed with alcohol a dissolved in benzene, filtered and precipitated by a y d of 2 emsr 81% of white crystals is as the addition of petroleum ether. The total yield obtained, having a melting point 01 Zoo-202 C. of the lactone of 2-chloro-3-carboxy-4-hydroxy- Up y liz n fr boiling 81001101, methyl-5-nitro-6-methylpyridine is 12.6 gms. or crystals of 3-cyano-4-ethoxymetl'iyl-6-meth171- 77% of theory. It may be recrystallized from DY OH are Obtained. which have a melting benzene and ethyl acetate, and has a melting point of 202.5 C. '50 point of 176-178 C.

Fifteen gms. cf y y Two and twenty-eight hundredths gms. oi the methylpyridone-Z are mixed with cc. of conl t n of 2; h1 -3- -4- t centrated hydrochloric acidv and heated at 5-n3ltro-6-metbylpyridine are dissolved in 120-125 C. for four hours. The reaction mixcc. oi. a mixture of ethyl acetate and 95% or is ethyl alcohol, 10 gms..or 5% palladium on barium melting point 225226 C. The picrate of this compound is made by mixing alcohol solutions of the same and picric acid. It is filtered and recrystallized from water or alcohol. The

-picrate has a melting point of 230 C., with decomposition.

Alternatively, 5.58 gms. of the lactone of 2-- chloro 3 carboxy -4-hydroxymethyl-5-nitro-6- methylpyridine is dissolved in 190 cc. of glacial acetic acid, 0.3 gm. platinum oxide added and the mixture shaken with hydrogen at three atmospheres pressure until three molecular equivalents are absorbed. The reduction is stopped, the mixture cooled, filtered and recrystallized from glacial acetic acid; The total yield of the lactone of 2-chloro-3-carboxy-4- hydroxymethyl-S-amirio 6 4 methylpyridine is 2.31 gms. or 48% of theory. It may be recrystallized directly from glacial acetic acid or from strong hydrochloric acid, by dilution and has a melting point of 280-282 C.

Five and ninety-five hundredths gms. of the lactone of 2-chloro-3-carboxy-4-hydroxymethyl- -amino-6-methylpyridine is suspended in 250 cc. of absolute alcohol with 10 gms.- palladium on barium carbonate as ,a catalyst and shaken with hydrogen at 2-3 atmospheres pressure and 60 C. until the theoretical quantity is absorbed.

The solution is filtered from the catalyst and cooled whereupon crystals are obtained. Additional crystals are obtained by evaporation of refluxed for three hours.

asaaoss at about 0 C. The diazo solution is decomposed by adding dropwise to bofling 50% sulfuric acid, the acid is exactly neutralized with sodium hydroxide, the water is removed by evaporation, and the lactone of 3-carboxy-4-hydroxymethyl- 5-hydroxy-6-methylpyridine is obtained by extraction with alcohol, M. P. 272-3 C. The latter compound is dissolved in anhydrous acetic acid and sodium amalgam is added until reaction is complete. The acetic solution is diluted with concentrated hydrochloric acid and The solution is then concentrated in vacuo and the hydrochloride of vitamin B0 is extracted with alcohol and crystallized by the addition of acetone. If desired, the vitamin Be free base can be obtained from the hydrochloride, and has-the formula 3,4-di- (hydroxym'ethyl) 5-hydroxy-S-methylpyridine.

Alternatively, the lactone of 3-carboxy-4- hydroxymethyl-5-hydroxy-6-methylpyridine is dissolved in hydrochloric acid and warmed on a boiling water bath. Granulated tin is added and the mixture heated for one hour. The solution is evaporated to dryness and the residue dissolved in water and treated with hydrogen sulphide to remove the tin: The filtrate is again evaporated to dryness and the vitamin B6 hydrochloride is recrystallized from alcohol and acetone.

Alternatively, the lactone of 3-carboxy-4- hydroxymethyl-5-hydroxy-6-methylpyridine is dissolved in water and reduced with hydrogen in a high pressure bomb at C. with copper chromite as the catalyst. After cooling to room temperature the solution is filtered from the catalyst and evaporated to dryness to obtain vitamin B6.

Modifications may be made in carrying out this invention without departing from the spirit and scope thereof.

I claim:

1. A member selected from the group consisting of the lactone of 4 3,-carboxy-4-hydroxymethyl-6-methy1pyridone-2, and the lactone of 3-carboxy-4-hydroxymethyl-5- nitro -6 methylpyrid0ne-2.

2. The lactone of 3 carboxy 4 hydroxymethyl-6-methylpyridone-2. 

